It is becoming increasingly more important to monitor the use of water in many sectors of society. As such, a variety of sprinkler controller systems are available that permit watering of vegetation only when soil moisture levels fall below a predetermined level. For example, U.S. Pat. No. 4,892,113 to Fattahi on Jan. 9, 1990 discloses such a system.
Currently available monitoring and control systems do not take into account air temperature as an important parameter in actuation of irrigation systems. For example, if air temperature is below 32.degree. F., current systems will still permit the actuation of irrigation systems. Moreover, if air temperature is high enough, watering vegetation will result in a high degree of evaporation. Consequently, there is a strong need for an irrigation control system that utilizes soil moisture levels and air temperature to determine optimal temperature and soil moisture levels for irrigation.
Currently available monitoring and control systems are also unnecessarily complex, requiring an external power source for moisture detectors. Moreover, many currently available monitoring and control systems require the use of alternating current, due to capacitive moisture sensoring techniques, which further add to the complexity and costs of such systems.
Clearly, then, a moisture monitoring and sprinkler control system is needed that not only inhibits actuation of the watering system when soil moisture is sufficient, but also inhibits actuation of the watering system when the air temperature is not within a specified range. Such a needed system would not require external power to the moisture sensors, and would function on DC voltages, thereby reducing complexity and cost of the system. The present invention fulfills these needs and provides further related advantages.